your heart's mitral valve does an awfully big job. letting blood from the left atrium of the heart into the left ventricle without loosing a drop is one of the toughest tasks in the circulatory system. in fact, if the system was suddenly opened at that point. the force of the valve closing would send blood five feet in the air. In the passage the author purpose is to:

(a) describe the circulatory system (b) convince readers of the stress of the mitral valve

Left chamber gets oxygenated blood from lungs through four aspiratory veins. There is a mitral or bicuspid valve between left chamber and left ventricle.  

so in the diastole phase of chamber blood get exhausted into the chamber and now the mitral valve is kept open with the goal that blood go into ventricle passively ,at that point in the atrial constriction rest blood around 30% gets purged into the ventricle.  

Presently what occurs, ventricle start withdrawal? Presently mitral valve get shut due to the weight that is happened in ventricle because of ventricular systole, and endeavored reverse of blood into left chamber.  

Presently ventricle contract as a shut chamber. During withdrawal, pressure inside increments.  

At the point when the weight inside the left ventricle increment in contrasted with the aortic weight semi lunar valve opens and blood is siphoned into the aorta.  

So extraordinary weight around 120 mph of weight are created in the ventricle during systole so as to conquer the weight in the aorta.  

So the weight is with the end goal that if the framework was opened out of nowhere the power of valve shutting would send blood five feet noticeable all around.  

so creator needs to state that it is significant that all the blood which is purged into the ventricles are required to go into the ventricles without losing a drop of blood.  

In such a case that some blood is staying in the ventricle there is decline in stroke volume and abatement in cardiovascular yield. Which will cause coronary illness and diminished tissue perfusion.so it is one of the hardest activity in the circulatory framework.  

So as long as all the blood gets exhausted into left ventricle there is mitral valve close unexpectedly to check any reverse of blood into chamber. What's more, the power of valve shutting is likewise high.

Option B is correct

Explanation:

He is convincing the reader to appreciate the stress of the mitral valve by emphasizing on the powerful work the mitral valve is performing every second.

b is the correct answer